Enhanced asthma-related fibroblast to myofibroblast transition is the result of profibrotic TGF-β/Smad2/3 pathway intensification and antifibrotic TGF-β/Smad1/5/(8)9 pathway impairment

Targeting IL-13 and IL-4 in Asthma: Therapeutic Implications on Airway Remodeling in Severe Asthma

Asthma is a chronic respiratory disorder affecting individuals across all age groups. It is characterized by airway inflammation and remodeling and leads to progressive airflow restriction. While corticosteroids remain a mainstay therapy, their efficacy is limited in severe asthma due to genetic and epigenetic alterations, as well as elevated pro-inflammatory cytokines interleukin-4 (IL-4), interleukin-13 (IL-13), and interleukin-5 (IL-5), which drive structural airway changes including subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia. This underscores the critical need for biologically targeted therapies. This review systematically examines the roles of IL-4 and IL-13, key drivers of type-2 inflammation, in airway remodeling and their potential as therapeutic targets. IL-4 orchestrates eosinophil recruitment, immunoglobulin class switching, and Th2 differentiation, whereas IL-13 directly modulates structural cells, including fibroblasts and epithelial cells, to promote mucus hypersecretion and extracellular matrix (ECM) deposition. Despite shared signaling pathways, IL-13 emerges as the dominant cytokine in remodeling processes including mucus hypersecretion, fibrosis and smooth muscle hypertrophy. While IL-4 primarily amplifies inflammatory cascades by driving IgE switching, promoting Th2 cell polarization that sustain cytokine release, and inducing chemokines to recruit eosinophils. In steroid-resistant severe asthma, biologics targeting IL-4/IL-13 show promise in reducing exacerbations and eosinophilic inflammation. However, their capacity to reverse established remodeling remains inconsistent, as clinical trials prioritize inflammatory biomarkers over long-term structural outcomes. This synthesis highlights critical gaps in understanding the durability of IL-4/IL-13 inhibition on airway structure and advocates for therapies combining biologics with remodeling-specific strategies. Through the integration of mechanistic insights and clinical evidence, this review emphasizes the need for long-term studies utilizing advanced imaging, histopathological techniques, and patient-reported outcomes to evaluate how IL-4/IL-13-targeted therapies alter airway remodeling and symptom burden, thereby informing more effective treatment approaches for severe, steroid-resistant asthma.

Role of the TGF-β cytokine and its gene polymorphisms in asthma etiopathogenesis

Transforming growth factor beta (TGF-β) is a pluripotent cytokine expressed by all cells of the human body which plays important roles in maintaining homeostasis and allowing for proper individual development. Disturbances in TGF-β signaling contribute to the development of many diseases and disorders, including cancer and organ fibrosis. One of the diseases with the best-characterized correlation between TGF-β action and etiopathogenesis is asthma. Asthma is the most common chronic inflammatory disease of the lower and upper respiratory tract, characterized by bronchial hyperresponsiveness to a number of environmental factors, leading to bronchospasm and reversible limitation of expiratory flow. TGF-β, in particular TGF-β1, is a key factor in the etiopathogenesis of asthma. TGF-β1 concentration in bronchoalveolar lavage fluid samples is elevated in atopic asthma, and TGF-β expression is increased in asthmatic bronchial samples. The expression of all TGF-β isoforms is affected by a number of single nucleotide polymorphisms found in the genes encoding these cytokines. Some of the SNPs that alter the level of TGF-β expression may be associated with the occurrence and severity of symptoms of asthma and other diseases. The TGF-β gene polymorphisms, which are the subject of this paper, are potential diagnostic factors. If properly used, these polymorphisms can facilitate the early and precise diagnosis of asthma, allowing for the introduction of appropriate therapy and reduction of asthma exacerbation frequency.

In vivo, in vitro, and in silico approaches in the detailed study of di-butyl phthalate (DBP), a plasticizer-induced lung fibrosis via Nrf-2/Keap-1/HO-1 pathway and its regulation

The alveolar epithelium is a crucial barrier against external threats, yet it becomes a key player in initiating pulmonary fibrosis when compromised. Despite its importance, the intricate relationship between, DBP exposure and alveolar epithelial cell injury ensuing pro-fibrotic effects remains poorly understood. Phthalates, ubiquitous in nature, pose a significant risk to lung health upon inhalation, acting as immune triggers that cause airway inflammation and epithelial damage. We aimed to investigate the impact of intranasal administration ofDi-butyl Phthalate (DBP) inhalation, and its probable effects on normal and asthmatic lungs. DBP was administered via intranasal route in normal and OVA-induced asthmatic mice. DBP exposure enhanced oxidative stress and inflammatory parameters, leading to exacerbated asthmatic response and oxidative lung damage. Enhanced accumulation of immune cells, bronchial thickening, and collagen deposition was noted in histopathological investigations of DBP-exposed lung sections. Curcumin, a plant-derived molecule, significantly mitigated DBP-exposed asthma exacerbations by suppressing NF-κB expression and enhancing NRF2 levels via the Nrf-2/Keap-1/HO-1 signaling pathway. FACS analysis revealed increased CD11b+ cells (32 %) in asthmatic mice which were reduced in the curcumin pre-treatment group (10.5 %). Enhanced epithelial to mesenchymal transition (EMT) was noted in mice lungs and A549 cells where E-cadherin expression was reduced as compared to Vimentin, and α-SMA. Apart from aggravated airway inflammation, DBP exposure damages healthy lungs also. MMP-9/TIMP-1 ratios and collagen-1 levels were restored which were enhanced after DBP exposure. Moreover, antioxidant enzyme levels such as NQO-1, HO-1, and Catalase were significantly enhanced (p < 0.01) and comparable to dexamethasone, a conventional corticosteroid. Notably, both dexamethasone and curcumin treatments effectively regulated the stimulation and accumulation of Nrf-2 in the nucleus, promoting antioxidant production and offering potential therapeutic benefits in mitigating pulmonary fibrosis. OVA and DBP alone caused DNA damage in the lung cells where increasedpercentage of damaged DNA movement in thetail, tail length, tail moment, and olive tail moment indicated severe damage in theDBP and OVA combined exposure strategies. Dexamethasone and Curcumin treatments reduced theextent of the DNA damage indicating anti-inflammatory and ant-oxidative potentials. Moreover, in silico studies are supportive of therapeutic potential of Curcumin and Dexamethasone in DBP-induced lung inflammation and fibrosis.

Enter the Matrix: Fibroblast-immune cell interactions shape extracellular matrix deposition in health and disease

Fibroblasts, non-hematopoietic cells of mesenchymal origin, are tissue architects which regulate the topography of tissues, dictate tissue resident cell types, and drive fibrotic disease. Fibroblasts regulate the composition of the extracellular matrix (ECM), a 3-dimensional network of macromolecules that comprise the acellular milieu of tissues. Fibroblasts can directly and indirectly regulate immune responses by secreting ECM and ECM-bound molecules to shape tissue structure and influence organ function. In this review, we will highlight recent studies which elucidate the mechanisms by which fibroblast-derived ECM factors (e.g., collagens, fibrillar proteins) regulate ECM architecture and subsequent immune responses, with a focus on macrophages. As examples of fibroblast-derived ECM proteins, we examine Collagen Triple Helix Repeat Containing 1 (CTHRC1) and Transforming Growth Factor-β-inducible protein (TGFBI), also known as BIGH3. We address the need for investigation into how diverse fibroblast populations coordinate immune responses by modulating ECM, including the fibroblast-ECM-immune axis and the precise molecular mediators and pathways which regulate these processes. Finally, we will outline how novel research identifying key regulators of ECM deposition is critical for therapeutic development for fibrotic diseases and cancer.

The Effects of Botulinum Toxin Type A on the Biological Behavior of Fibroblasts on Silicone Implants

BACKGROUND

Capsular contracture is one of the most severe complications following breast augmentation surgery. It has been reported that botulinum toxin Type A (BTX-A) can inhibit capsular contracture, but the exact mechanisms remain unclear. Therefore, this study aims to explore the potential mechanisms behind BTX-A's inhibition of capsular contracture by observing its effects on the biological behavior of fibroblasts and its impact on the TGF-β/Smad signaling pathway.

METHODS

In vitro experiments involved culturing fibroblasts on PDMS surfaces, subsequently treating them with various concentrations of BTX-A. Fibroblast proliferation activity was assessed using the CCK-8 assay, while the migration and cytoskeletal morphology of the fibroblasts were meticulously examined. ELISA was utilized to quantify the expression of fibrosis-related cytokines. Gene and protein expressions related to the TGF-β/Smad pathway were analyzed through real-time PCR and Western blotting techniques.

RESULTS

BTX-A moderately enhanced the early proliferation and migration of fibroblasts on the surface of PDMS silicone sheets and reduced the synthesis of collagen types I and III. Furthermore, under the influence of BTX-A, the expression of TGF-βR2 and α-SMA in the TGF-β/Smad pathway was significantly inhibited.

CONCLUSIONS

This study demonstrates that BTX-A can inhibit fibroblast differentiation by downregulating the expression of TGF-βR2, thereby suppressing the TGF-β/Smad pathway. This suggests a possible mechanism through which BTX-A mitigates capsular contracture.

NO LEVEL ASSIGNED

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Exploring Smad5: a review to pave the way for a deeper understanding of the pathobiology of common respiratory diseases

Smad5 (small mothers against decapentaplegic 5) protein is a receptor-regulated member of the Smad family proteins, mainly participating in the bone morphogenetic protein (BMP) signaling pathway in its phosphorylated form. This article will provide a detailed review of Smad5, focusing on its gene characteristics, protein structure, and subcellular localization properties. We will also explore the related signaling pathways and the mechanisms of Smad5 in respiratory diseases, including chronic obstructive pulmonary disease (COPD), bronchial asthma, pulmonary arterial hypertension(PAH), lung cancer, and idiopathic pulmonary fibrosis (IPF). Additionally, the review will cover aspects such as proliferation, differentiation, apoptosis, anti-fibrosis, and mitochondrial function metabolism. In addition, the review will cover aspects of proliferation, differentiation, apoptosis, anti-fibrosis and functional mitochondrial metabolism related to the above topics. Numerous studies suggest that Smad5 may play a unique and important role in the pathogenesis of respiratory system diseases. However, in previous research, Smad5 was mainly used to broadly determine the activation of the BMP signaling pathway, and its own function has not been given much attention. It is worth noting that Smad5 has distinct nuclear-cytoplasmic distribution characteristics different from Smad1 and Smad8. It can undergo significant nuclear-cytoplasmic shuttling when intracellular pH (pHi) changes, playing important roles in both the classical BMP signaling pathway and non-BMP signaling pathways. Given that Smad5 can move intracellularly in response to changes in physicochemical properties, its cellular localization may play a crucial role in the development of respiratory diseases. This article will explore the possibility that its distribution characteristics may be an important factor that is easily overlooked and not adequately considered in disease research.

Activins and Inhibins in Cardiovascular Pathophysiology

Activins and inhibins, members of the transforming growth factor β (TGFβ) superfamily, were initially recognized for their opposing effects on the secretion of follicle-stimulating hormone. Subsequent research has demonstrated their broader biological roles across various tissue types. Primarily, activins and inhibins function through the classical TGFβ SMAD signaling pathway, but studies suggest that they also act through other pathways, with their specific signaling being complex and context-dependent. Recent research has identified significant roles for activins and inhibins in the cardiovascular system. Their actions in other systems and their signaling pathways show strong correlations with the development and progression of cardiovascular diseases, indicating potential broader roles in the cardiovascular system. This review summarizes the progress in research on the biological functions and mechanisms of activins and inhibins and their signaling pathways in cardiovascular diseases, offering new insights for the prevention and treatment of cardiovascular diseases.

MAP3K19 Promotes the Progression of Tuberculosis-Induced Pulmonary Fibrosis Through Activation of the TGF-β/Smad2 Signaling Pathway

Tuberculosis-induced pulmonary fibrosis (PF) is a chronic, irreversible interstitial lung disease, which severely affects lung ventilation and air exchange, leading to respiratory distress, impaired lung function, and ultimately death. As previously reported, epithelial-mesenchymal transition (EMT) and fibrosis in type II alveolar epithelial cells (AEC II) are two critical processes that contributes to the initiation and progression of tuberculosis-related PF, but the underlying pathological mechanisms remain unclear. In this study, through performing Real-Time quantitative PCR (RT-qPCR), Western blot, immunohistochemistry, and immunofluorescence staining assay, we confirmed that the expression levels of EMT and fibrosis-related biomarkers were significantly increased in lung tissues with tuberculosis-associated PF in vivo and Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain-infected AEC II cells in vitro. Besides, we noticed that the mitogen-activated protein kinase 19 (MAP3K19) was aberrantly overexpressed in PF models, and silencing of MAP3K19 significantly reduced the expression levels of fibronectin, collagen type I, and alpha-smooth muscle actin to decrease fibrosis, and upregulated E-cadherin and downregulated vimentin to suppress EMT in BCG-treated AEC II cells. Then, we uncovered the underlying mechanisms and found that BCG synergized with MAP3K19 to activate the pro-inflammatory transforming growth factor-beta (TGF-β)/Smad2 signal pathway in AEC II cells, and BCG-induced EMT process and fibrosis in AEC II cells were all abrogated by co-treating cells with TGF-β/Smad2 signal pathway inhibitor LY2109761. In summary, our results uncovered the underlying mechanisms by which the MAP3K19/TGF-β/Smad2 signaling pathway regulated EMT and fibrotic phenotypes of AEC II cells to facilitate the development of tuberculosis-associated PF, and these findings will provide new ideas and biomarkers to ameliorate tuberculosis-induced PF in clinic.

Genome-Wide DNA methylation profile analysis identifies differentially methylated loci associated with personal PM2.5 exposure in adults with asthma

Particulate matter with aerodynamic diameters ≤2.5 µm (PM2.5) is a major environmental risk factor for acute asthma exacerbation, and the underlying mechanism is not completely understood. Studies have indicated that DNA methylation is a potential mechanism linking PM2.5 to its health effects. We conducted a panel study involving 24 adult patients with asthma in Beijing,China between 2017 and 2019. PM2.5 and other atmospheric pollutant exposure data were repeatedly measured. Blood samples were collected for genome-wide DNA methylation analysis. A linear mixed-effects (LME) model was conducted to identify differentially methylated probes (DMPs) associated with PM2.5 exposure. After filtering out probes that did not meet the criteria through quality control, 811,001 CpG sites were included in the LME model, and 36 DMPs were strongly associated with personal PM2.5 exposure at false discovery rate (FDR) < 0.05, of which 22 and 14 DMPs negatively and positively correlated with personal PM2.5 exposure, respectively. Functional analysis revealed that DMPs affected smooth muscle cell contraction and development, extracellular matrix synthesis and secretion, T cell activation and differentiation, and inflammatory factor production. This study provides evidence linking personal PM2.5 exposure to genome-wide DNA methylation in adult patients with asthma. Identifying enrichment pathways can provide biological insights into the acute health effects of PM2.5.

The Role of Transforming Growth Factor-β (TGF-β) in Asthma and Chronic Obstructive Pulmonary Disease (COPD)

Asthma and chronic obstructive pulmonary disease (COPD) represent chronic inflammatory respiratory disorders that, despite having distinct pathophysiological underpinnings, both feature airflow obstruction and respiratory symptoms. A critical component in the pathogenesis of each condition is the transforming growth factor-β (TGF-β), a multifunctional cytokine that exerts varying influences across these diseases. In asthma, TGF-β is significantly involved in airway remodeling, a key aspect marked by subepithelial fibrosis, hypertrophy of the smooth muscle, enhanced mucus production, and suppression of emphysema development. The cytokine facilitates collagen deposition and the proliferation of fibroblasts, which are crucial in the structural modifications within the airways. In contrast, the role of TGF-β in COPD is more ambiguous. It initially acts as a protective agent, fostering tissue repair and curbing inflammation. However, prolonged exposure to environmental factors such as cigarette smoke causes TGF-β signaling malfunction. Such dysregulation leads to abnormal tissue remodeling, marked by excessive collagen deposition, enlargement of airspaces, and, thus, accelerated development of emphysema. Additionally, TGF-β facilitates the epithelial-to-mesenchymal transition (EMT), a process contributing to the phenotypic alterations observed in COPD. A thorough comprehension of the multifaceted role of TGF-β in asthma and COPD is imperative for elaborating precise therapeutic interventions. We review several promising approaches that alter TGF-β signaling. Nevertheless, additional studies are essential to delineate further the specific mechanisms of TGF-β dysregulation and its potential therapeutic impacts in these chronic respiratory diseases.

Chondroitin Sulfate-Based Nanocapsules as Nanocarriers for Drugs and Nutraceutical Supplements

Oil-core nanocapsules (NCs, also known as nanoemulsions) are of great interest due to their application as efficient carriers of various lipophilic bioactives, such as drugs. Here, we reported for the first time the preparation and characterization of NCs consisting of chondroitin sulfate (CS)-based shells and liquid oil cores. For this purpose, two amphiphilic CS derivatives (AmCSs) were obtained by grafting the polysaccharide chain with octadecyl or oleyl groups. AmCS-based NCs were prepared by an ultrasound-assisted emulsification of an oil phase consisting of a mixture of triglyceride oil and vitamin E in a dispersion of AmCSs. Dynamic light scattering and cryo-transmission electron microscopy showed that the as-prepared core-shell NCs have typical diameters in the range of 30-250 nm and spherical morphology. Since CS is a strong polyanion, these particles have a very low surface potential, which promotes their stabilization. The cytotoxicity of the CS derivatives and CS-based NCs and their impact on cell proliferation were analyzed using human keratinocytes (HaCaTs) and primary human skin fibroblasts (HSFs). In vitro studies showed that AmCSs dispersed in an aqueous medium, exhibiting mild cytotoxicity against HaCaTs, while for HSFs, the harmful effect was observed only for the CS derivative with octadecyl side groups. However, the nanocapsules coated with AmCSs, especially those filled with vitamin E, show high biocompatibility with human skin cells. Due to their stability under physiological conditions, the high encapsulation efficiency of their hydrophobic compounds, and biocompatibility, AmCS-based NCs are promising carriers for the topical delivery of lipophilic bioactive compounds.

Advances in co-pathogenesis of the united airway diseases

According to the concept of "united airway diseases", the airway is a single organ in which upper and lower airway diseases are commonly comorbid. A range of inflammatory factors have been found to play an important role in the chain reaction of upper and lower airway diseases. However, the amount of research on this concept remains limited. The underlying mechanism of the relationship between typical diseases of the united airway, such as asthma, allergic rhinitis, and chronic sinusitis, also needs to be further explored. This review highlights the interaction between upper and lower respiratory diseases gathered from epidemiological, histoembryology, neural mechanistic, microbiological, and clinical studies, revealing the relationship between the upper and lower respiratory tracts.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Canonical Wnt and TGF-β/BMP signaling enhance melanocyte regeneration but suppress invasiveness, migration, and proliferation of melanoma cells

Melanoma is the deadliest form of skin cancer and develops from the melanocytes that are responsible for the pigmentation of the skin. The skin is also a highly regenerative organ, harboring a pool of undifferentiated melanocyte stem cells that proliferate and differentiate into mature melanocytes during regenerative processes in the adult. Melanoma and melanocyte regeneration share remarkable cellular features, including activation of cell proliferation and migration. Yet, melanoma considerably differs from the regenerating melanocytes with respect to abnormal proliferation, invasive growth, and metastasis. Thus, it is likely that at the cellular level, melanoma resembles early stages of melanocyte regeneration with increased proliferation but separates from the later melanocyte regeneration stages due to reduced proliferation and enhanced differentiation. Here, by exploiting the zebrafish melanocytes that can efficiently regenerate and be induced to undergo malignant melanoma, we unravel the transcriptome profiles of the regenerating melanocytes during early and late regeneration and the melanocytic nevi and malignant melanoma. Our global comparison of the gene expression profiles of melanocyte regeneration and nevi/melanoma uncovers the opposite regulation of a substantial number of genes related to Wnt signaling and transforming growth factor beta (TGF-β)/(bone morphogenetic protein) BMP signaling pathways between regeneration and cancer. Functional activation of canonical Wnt or TGF-β/BMP pathways during melanocyte regeneration promoted melanocyte regeneration but potently suppressed the invasiveness, migration, and proliferation of human melanoma cells in vitro and in vivo. Therefore, the opposite regulation of signaling mechanisms between melanocyte regeneration and melanoma can be exploited to stop tumor growth and develop new anti-cancer therapies.

Small-Molecule Probes as Pharmacological Tools for the Bone Morphogenetic Protein Signaling Pathway

The bone morphogenetic protein (BMP) pathway is highly conserved and plays central roles in health and disease. The quality and quantity of its signaling outputs are regulated at multiple levels, offering pharmacological options for targeted modulation. Both target-centric and phenotypic drug discovery (PDD) approaches were applied to identify small-molecule BMP inhibitors and stimulators. In this Review, we accumulated and systematically classified the different reported chemotypes based on their targets as well as modes-of-action, and herein we illustrate the discovery history of selected candidates. A comprehensive summary of available biochemical, cellular, and in vivo activities is provided for the most relevant BMP modulators, along with recommendations on their preferred use as chemical probes to study BMP-related (patho)physiological processes. There are a number of high-quality probes used as BMP inhibitors that potently and selectively interrogate the kinase activities of distinct type I (16 chemotypes available) and type II receptors (3 chemotypes available). In contrast, only a few high-quality BMP stimulator modalities have been introduced to the field due to a lack of profound target knowledge. FK506-derived macrolides such as calcineurin-sparing FKBP12 inhibitors currently represent the best-characterized chemical tools for direct activation of BMP-SMAD signaling at the receptor level. However, several PDD campaigns succeeded in expanding the druggable space of BMP stimulators. Albeit the majority of them do not entirely fulfill the strict chemical probe criteria, many chemotypes exhibit unique and unrecognized mechanisms as pathway potentiators or synergizers, serving as valuable pharmacological tools for BMP perturbation.

Hypoxia enhances anti-fibrotic properties of extracellular vesicles derived from hiPSCs via the miR302b-3p/TGFβ/SMAD2 axis

BACKGROUND

Cardiac fibrosis is one of the top killers among fibrotic diseases and continues to be a global unaddressed health problem. The lack of effective treatment combined with the considerable socioeconomic burden highlights the urgent need for innovative therapeutic options. Here, we evaluated the anti-fibrotic properties of extracellular vesicles (EVs) derived from human induced pluripotent stem cells (hiPSCs) that were cultured under various oxygen concentrations.

METHODS

EVs were isolated from three hiPSC lines cultured under normoxia (21% O2; EV-N) or reduced oxygen concentration (hypoxia): 3% O2 (EV-H3) or 5% O2 (EV-H5). The anti-fibrotic activity of EVs was tested in an in vitro model of cardiac fibrosis, followed by a detailed investigation of the underlying molecular mechanisms. Sequencing of EV miRNAs combined with bioinformatics analysis was conducted and a selected miRNA was validated using a miRNA mimic and inhibitor. Finally, EVs were tested in a mouse model of angiotensin II-induced cardiac fibrosis.

RESULTS

We provide evidence that an oxygen concentration of 5% enhances the anti-fibrotic effects of hiPS-EVs. These EVs were more effective in reducing pro-fibrotic markers in activated human cardiac fibroblasts, when compared to EV-N or EV-H3. We show that EV-H5 act through the canonical TGFβ/SMAD pathway, primarily via miR-302b-3p, which is the most abundant miRNA in EV-H5. Our results show that EV-H5 not only target transcripts of several profibrotic genes, including SMAD2 and TGFBR2, but also reduce the stiffness of activated fibroblasts. In a mouse model of heart fibrosis, EV-H5 outperformed EV-N in suppressing the inflammatory response in the host and by attenuating collagen deposition and reducing pro-fibrotic markers in cardiac tissue.

CONCLUSIONS

In this work, we provide evidence of superior anti-fibrotic properties of EV-H5 over EV-N or EV-H3. Our study uncovers that fine regulation of oxygen concentration in the cellular environment may enhance the anti-fibrotic effects of hiPS-EVs, which has great potential to be applied for heart regeneration.

Role of transforming growth factor-β in airway remodelling in bronchiolitis obliterans

Airway remodelling is the main pathological mechanism of bronchiolitis obliterans (BO). Several studies have found that transforming growth factor-β (TGF-β) expression is increased in BO during airway remodelling, where it plays an important role in various biological processes by binding to its receptor complex to activate multiple signalling proteins and pathways. This review examines the role of TGF-β in airway remodelling in BO and its potential as a therapeutic target, highlighting the mechanisms of TGF-β activation and signalling, cellular targets of TGF-β actions, and research progress in TGF-β signalling and TGF-β-mediated processes.

Gene-Smoking Interaction Analysis for the Identification of Novel Asthma-Associated Genetic Factors

Asthma is a complex heterogeneous disease caused by gene-environment interactions. Although numerous genome-wide association studies have been conducted, these interactions have not been systemically investigated. We sought to identify genetic factors associated with the asthma phenotype in 66,857 subjects from the Health Examination Study, Cardiovascular Disease Association Study, and Korea Association Resource Study cohorts. We investigated asthma-associated gene-environment (smoking status) interactions at the level of single nucleotide polymorphisms, genes, and gene sets. We identified two potentially novel (SETDB1 and ZNF8) and five previously reported (DM4C, DOCK8, MMP20, MYL7, and ADCY9) genes associated with increased asthma risk. Numerous gene ontology processes, including regulation of T cell differentiation in the thymus (GO:0033081), were significantly enriched for asthma risk. Functional annotation analysis confirmed the causal relationship between five genes (two potentially novel and three previously reported genes) and asthma through genome-wide functional prediction scores (combined annotation-dependent depletion, deleterious annotation of genetic variants using neural networks, and RegulomeDB). Our findings elucidate the genetic architecture of asthma and improve the understanding of its biological mechanisms. However, further studies are necessary for developing preventive treatments based on environmental factors and understanding the immune system mechanisms that contribute to the etiology of asthma.

Bronchial Fibroblasts from Asthmatic Patients Display Impaired Responsiveness to Direct Current Electric Fields (dcEFs)

Accumulating evidence suggests that an important role is played by electric signals in modifying cell behaviour during developmental, regenerative and pathological processes. However, their role in asthma has not yet been addressed. Bronchial fibroblasts have recently been identified having important roles in asthma development. Therefore, we adapted an experimental approach based on the lineages of human bronchial fibroblasts (HBF) derived from non-asthmatic (NA) donors and asthmatic (AS) patients to elucidate whether their reactivity to direct current electric fields (dcEF) could participate in the asthmatic process. The efficient responsiveness of NA HBF to an electric field in the range of 2-4 V/cm was illustrated based on the perpendicular orientation of long axes of the cells to the field lines and their directional movement towards the anode. These responses were related to the activity of TGF-β signalling, as the electrotaxis and re-orientation of NA HBF polarity was impaired by the inhibitors of canonical and non-canonical TGF-β-dependent pathways. A similar tendency towards perpendicular cell-dcEF orientation was observed for AS HBF. However, their motility remained insensitive to the electric field applied at 2-4 V/cm. Collectively, these observations demonstrate the sensitivity of NA HBF to dcEF, as well as the inter-relations between this parameter and the canonical and non-canonical TGF-β pathways, and the differences between the electrotactic responses of NA and AS HBF point to the possible role of their dcEFs in desensitisation in the asthmatic process. This process may impair the physiologic behaviour of AS HBF functions, including cell motility, ECM deposition, and contractility, thus promoting bronchial wall remodelling, which is a characteristic of bronchial asthma.

Ιnterleukin-17A-Enriched Neutrophil Extracellular Traps Promote Immunofibrotic Aspects of Childhood Asthma Exacerbation

Childhood asthma is a chronic inflammatory airway disorder that can drive tissue remodeling. Neutrophils are amongst the most prominent inflammatory cells contributing to disease manifestations and may exert a potent role in the progression of inflammation to fibrosis. However, their role in asthma exacerbation is still understudied. Here, we investigate the association between neutrophil extracellular traps (NETs) and lung fibroblasts in childhood asthma pathophysiology using serum samples from pediatric patients during asthma exacerbation. Cell-based assays and NETs/human fetal lung fibroblast co-cultures were deployed. Increased levels of NETs and interleukin (IL)-17A were detected in the sera of children during asthma exacerbation. The in vitro stimulation of control neutrophils using the sera from pediatric patients during asthma exacerbation resulted in IL-17A-enriched NET formation. The subsequent co-incubation of lung fibroblasts with in vitro-generated IL-17A-enriched NETs led fibroblasts to acquire a pre-fibrotic phenotype, as assessed via enhanced CCN2 expression, migratory/healing capacity, and collagen release. These data uncover the important pathogenic role of the NET/IL-17A axis in asthma exacerbation, linking lung inflammation to fibroblast dysfunction and fibrosis.

PPARδ Agonist GW501516 Suppresses the TGF-β-Induced Profibrotic Response of Human Bronchial Fibroblasts from Asthmatic Patients

The airway wall remodeling observed in asthma is associated with subepithelial fibrosis and enhanced activation of human bronchial fibroblasts (HBFs) in the fibroblast to myofibroblast transition (FMT), induced mainly by transforming growth factor-β (TGF-β). The relationships between asthma severity, obesity, and hyperlipidemia suggest the involvement of peroxisome proliferator-activated receptors (PPARs) in the remodeling of asthmatic bronchi. In this study, we investigated the effect of PPARδ ligands (GW501516 as an agonist, and GSK0660 as an antagonist) on the FMT potential of HBFs derived from asthmatic patients cultured in vitro. This report shows, for the first time, the inhibitory effect of a PPARδ agonist on the number of myofibroblasts and the expression of myofibroblast-related markers-α-smooth muscle actin, collagen 1, tenascin C, and connexin 43-in asthma-related TGF-β-treated HBF populations. We suggest that actin cytoskeleton reorganization and Smad2 transcriptional activity altered by GW501516 lead to the attenuation of the FMT in HBF populations derived from asthmatics. In conclusion, our data demonstrate that a PPARδ agonist stimulates antifibrotic effects in an in vitro model of bronchial subepithelial fibrosis. This suggests its potential role in the development of a possible novel therapeutic approach for the treatment of subepithelial fibrosis during asthma.

Co-Expression Analysis of Airway Epithelial Transcriptome in Asthma Patients with Eosinophilic vs. Non-Eosinophilic Airway Infiltration

Asthma heterogeneity complicates the search for targeted treatment against airway inflammation and remodeling. We sought to investigate relations between eosinophilic inflammation, a phenotypic feature frequent in severe asthma, bronchial epithelial transcriptome, and functional and structural measures of airway remodeling. We compared epithelial gene expression, spirometry, airway cross-sectional geometry (computed tomography), reticular basement membrane thickness (histology), and blood and bronchoalveolar lavage (BAL) cytokines of n = 40 moderate to severe eosinophilic (EA) and non-eosinophilic asthma (NEA) patients distinguished by BAL eosinophilia. EA patients showed a similar extent of airway remodeling as NEA but had an increased expression of genes involved in the immune response and inflammation (e.g., KIR3DS1), reactive oxygen species generation (GYS2, ATPIF1), cell activation and proliferation (ANK3), cargo transporting (RAB4B, CPLX2), and tissue remodeling (FBLN1, SOX14, GSN), and a lower expression of genes involved in epithelial integrity (e.g., GJB1) and histone acetylation (SIN3A). Genes co-expressed in EA were involved in antiviral responses (e.g., ATP1B1), cell migration (EPS8L1, STOML3), cell adhesion (RAPH1), epithelial-mesenchymal transition (ASB3), and airway hyperreactivity and remodeling (FBN3, RECK), and several were linked to asthma in genome- (e.g., MRPL14, ASB3) or epigenome-wide association studies (CLC, GPI, SSCRB4, STRN4). Signaling pathways inferred from the co-expression pattern were associated with airway remodeling (e.g., TGF-β/Smad2/3, E2F/Rb, and Wnt/β-catenin).

Combinatorial prophylactic effect of phlorotannins with photobiomodulation against tracheal stenosis

Several conventional treatments are used to manage tracheal stenosis after intubation and surgical procedures; however, patients are at risk of restenosis because of the absence of effective preventative therapy. In this study, we evaluate the biomodulatory effect of PT-combined blue light (BL) PBM in tracheostomal stenosis-induced animal models. The PT-combined BL group showed a significant decrease in the fibrotic protein synthesis by downregulating the release of stenosis-triggering fibrotic signals, without cytotoxicity or thermal damage. Moreover, the combined treatment ameliorated excessive granulation and collagen formation, and consequently preserved the opening of the tracheostoma ten days after fenestration. The current study demonstrated the biomodulatory effect of PT-combined BL on human tracheal fibroblasts and tracheal fenestration rodent models. Hence, PT-combined BL has the potential to be an effective preventative treatment for tracheal stenosis but also as an alternative option for fibrotic disorders.

Activation of pancreatic stellate cells attenuates intracellular Ca2+ signals due to downregulation of TRPA1 and protects against cell death induced by alcohol metabolites

Alcohol abuse, an increasing problem in developed societies, is one of the leading causes of acute and chronic pancreatitis. Alcoholic pancreatitis is often associated with fibrosis mediated by activated pancreatic stellate cells (PSCs). Alcohol toxicity predominantly depends on its non-oxidative metabolites, fatty acid ethyl esters, generated from ethanol and fatty acids. Although the role of non-oxidative alcohol metabolites and dysregulated Ca²⁺ signalling in enzyme-storing pancreatic acinar cells is well established as the core mechanism of pancreatitis, signals in PSCs that trigger fibrogenesis are less clear. Here, we investigate real-time Ca²⁺ signalling, changes in mitochondrial potential and cell death induced by ethanol metabolites in quiescent vs TGF-β-activated PSCs, compare the expression of Ca²⁺ channels and pumps between the two phenotypes and the consequences these differences have on the pathogenesis of alcoholic pancreatitis. The extent of PSC activation in the pancreatitis of different aetiologies has been investigated in three animal models. Unlike biliary pancreatitis, alcohol-induced pancreatitis results in the activation of PSCs throughout the entire tissue. Ethanol and palmitoleic acid (POA) or palmitoleic acid ethyl ester (POAEE) act directly on quiescent PSCs, inducing cytosolic Ca²⁺ overload, disrupting mitochondrial functions, and inducing cell death. However, activated PSCs acquire remarkable resistance against ethanol metabolites via enhanced Ca²⁺-handling capacity, predominantly due to the downregulation of the TRPA1 channel. Inhibition or knockdown of TRPA1 reduces EtOH/POA-induced cytosolic Ca²⁺ overload and protects quiescent PSCs from cell death, similarly to the activated phenotype. Our results lead us to review current dogmas on alcoholic pancreatitis. While acinar cells and quiescent PSCs are prone to cell death caused by ethanol metabolites, activated PSCs can withstand noxious signals and, despite ongoing inflammation, deposit extracellular matrix components. Modulation of Ca²⁺ signals in PSCs by TRPA1 agonists/antagonists could become a strategy to shift the balance of tissue PSCs towards quiescent cells, thus limiting pancreatic fibrosis.

Neuro-Immune Regulation in Inflammation and Airway Remodeling of Allergic Asthma

Allergic asthma is a common chronic inflammation of the airways and causes airway remodeling eventually. For a long time, investigators have been focusing on the immunological mechanism of asthma. However, in recent years, the role of neuro-regulation in the occurrence of asthma has gradually attracted investigators’ attention. In this review, we firstly describe neuro-immune regulation in inflammation of allergic asthma from two aspects: innate immunity and adaptive immunity. Secondly, we introduce neuro-immune regulation in airway remodeling of asthma. Finally, we prospect the role of pulmonary neuroendocrine cells in the development of asthma. In general, the amount of researches is limited. Further researches on the neural regulation during the occurrence of asthma will help us clarify the mechanism of asthma more comprehensively and find more effective ways to prevent and control asthma.

Pathobiology of Airway Remodeling in Asthma: The Emerging Role of Integrins

Airway remodeling is a complex clinical feature of asthma that involves long-term disruption and modification of airway architecture, which contributes significantly to airway hyperresponsiveness (AHR) and lung function decline. It is characterized by thickening of the airway smooth muscle layer, deposition of a matrix below the airway epithelium, resulting in subepithelial fibrosis, changes within the airway epithelium, leading to disruption of the barrier, and excessive mucous production and angiogenesis within the airway wall. Airway remodeling contributes to stiffer and less compliant airways in asthma and leads to persistent, irreversible airflow obstruction. Current asthma treatments aim to reduce airway inflammation and exacerbations but none are targeted towards airway remodeling. Inhibiting the development of airway remodeling or reversing established remodeling has the potential to dramatically improve symptoms and disease burden in asthmatic patients. Integrins are a family of transmembrane heterodimeric proteins that serve as the primary receptors for extracellular matrix (ECM) components, mediating cell-cell and cell-ECM interactions to initiate intracellular signaling cascades. Cells present within the lungs, including structural and inflammatory cells, express a wide and varying range of integrin heterodimer combinations and permutations. Integrins are emerging as an important regulator of inflammation, repair, remodeling, and fibrosis in the lung, particularly in chronic lung diseases such as asthma. Here, we provide a comprehensive summary of the current state of knowledge on integrins in the asthmatic airway and how these integrins promote the remodeling process, and emphasize their potential involvement in airway disease.

BMP7-based peptide agonists of BMPR1A protect the left ventricle against pathological remodeling induced by pressure overload

Aortic stenosis (AS) exposes the left ventricle (LV) to pressure overload leading to detrimental LV remodeling and heart failure. In animal models of cardiac injury or hemodynamic stress, bone morphogenetic protein-7 (BMP7) protects LV against remodeling by counteracting TGF-β effects. BMP receptor 1A (BMPR1A) might mediate BMP7 antifibrotic effects. Herein we evaluated BMP7-based peptides, THR123 and THR184, agonists of BMPR1A, as cardioprotective drugs in a pressure overload model. We studied patients with AS, mice subjected to four-week transverse aortic constriction (TAC) and TAC release (de-TAC). The LV of AS patients and TAC mice featured Bmpr1a downregulation. Also, pSMAD1/5/(8)9 was reduced in TAC mice. Pre-emptive treatment of mice with THR123 and THR184, during the four-week TAC period, normalized pSMAD1/5/(8)9 levels in the LV, attenuated overexpression of remodeling-related genes (Col 1α1, β-MHC, BNP), palliated structural damage (hypertrophy and fibrosis) and alleviated LV dysfunction (systolic and diastolic). THR184 administration, starting fifteen days after TAC, halted the ongoing remodeling and partially reversed LV dysfunction. The reverse remodeling after pressure overload release was facilitated by THR184. Both peptides diminished the TGF-β1-induced hypertrophic gene program in cardiomyocytes, collagen transcriptional activation in fibroblasts, and differentiation of cardiac fibroblasts to myofibroblasts. Molecular docking suggests that both peptides bind with similar binding energies to the BMP7 binding domain at the BMPR1A. The present study results provide a preclinical proof-of-concept of potential therapeutic benefits of BMP7-based small peptides, which function as agonists of BMPR1A, against the pathological LV remodeling in the context of aortic stenosis.

Asthmatic Eosinophils Alter the Gene Expression of Extracellular Matrix Proteins in Airway Smooth Muscle Cells and Pulmonary Fibroblasts

The impaired production of extracellular matrix (ECM) proteins by airway smooth muscle cells (ASMC) and pulmonary fibroblasts (PF) is a part of airway remodeling in asthma. This process might be influenced by eosinophils that migrate to the airway and abundantly secrete various cytokines, including TGF-β. We aimed to investigate the effect of asthmatic eosinophils on the gene expression of ECM proteins in ASMC and PF. A total of 34 study subjects were recruited: 14 with allergic asthma (AA), 9 with severe non-allergic eosinophilic asthma (SNEA), and 11 healthy subjects (HS). All AA patients underwent bronchial allergen challenge with D. pteronyssinus. The peripheral blood eosinophils were isolated using high-density centrifugation and magnetic separation. The individual cell cultures were made using hTERT ASMC and MRC-5 cell lines and the subjects' eosinophils. The gene expression of ECM and the TGF-β signaling pathway was analyzed using qRT-PCR. We found that asthmatic eosinophils significantly promoted collagen I, fibronectin, versican, tenascin C, decorin, vitronectin, periostin, vimentin, MMP-9, ADAM33, TIMP-1, and TIMP-2 gene expression in ASMC and collagen I, collagen III, fibronectin, elastin, decorin, MMP-2, and TIMP-2 gene expression in PF compared with the HS eosinophil effect. The asthmatic eosinophils significantly increased the gene expression of several canonical and non-canonical TGF-β signaling pathway components in ASMC and PF compared with the HS eosinophil effect. The allergen-activated AA and SNEA eosinophils had a greater effect on these changes. In conclusion, asthmatic eosinophils, especially SNEA and allergen-activated eosinophils, imbalanced the gene expression of ECM proteins and their degradation-regulating proteins. These changes were associated with increased gene expression of TGF-β signaling pathway molecules in ASMC and PF.

PD-L1 mediates lung fibroblast to myofibroblast transition through Smad3 and β-catenin signaling pathways

Programmed death ligand-1 (PD-L1) is an immune checkpoint protein that has been linked with idiopathic pulmonary fibrosis (IPF) and fibroblast to myofibroblast transition (FMT). However, it remains largely unclear how PD-L1 mediates this process. We found significantly increased PD-L1 in the lungs of idiopathic pulmonary fibrosis patients and mice with pulmonary fibrosis induced by bleomycin and TGF-β. In primary human lung fibroblasts (HLFs), TGF-β induced PD-L1 expression that is dependent on both Smad3 and p38 pathways. PD-L1 knockdown using siRNA significantly attenuated TGF-β-induced expression of myofibroblast markers α-SMA, collagen-1, and fibronectin in normal and IPF HLFs. Further, we found that PD-L1 interacts with Smad3, and TGF-β induces their interaction. Interestingly, PD-L1 knockdown reduced α-SMA reporter activity induced by TGF-β in HLFs, suggesting that PD-L1 might act as a co-factor of Smad3 to promote target gene expression. TGF-β treatment also phosphorylates GSK3β and upregulates β-catenin protein levels. Inhibiting β-catenin signaling with the pharmaceutical inhibitor ICG001 significantly attenuated TGF-β-induced FMT. PD-L1 knockdown also attenuated TGF-β-induced GSK3β phosphorylation/inhibition and β-catenin upregulation, implicating GSK3β/β-catenin signaling in PD-L1-mediated FMT. Collectively, our findings demonstrate that fibroblast PD-L1 may promote pulmonary fibrosis through both Smad3 and β-catenin signaling and may represent a novel interventional target for IPF.

Discrimination between NSIP- and IPF-Derived Fibroblasts Based on Multi-Parameter Characterization of Their Growth, Morphology and Physic-Chemical Properties

Background: The aim of the research presented here was to find a set of parameters enabling discrimination between three types of fibroblasts, i.e., healthy ones and those derived from two disorders mimicking each other: idiopathic pulmonary fibrosis (IPF), and nonspecific interstitial pneumonia (NSIP). Methods: The morphology and growth of cells were traced using fluorescence microscopy and analyzed quantitatively using cell proliferation and substrate cytotoxicity indices. The viability of cells was recorded using MTS assays, and their stiffness was examined using atomic force microscopy (AFM) working in force spectroscopy (FS) mode. To enhance any possible difference in the examined parameters, experiments were performed with cells cultured on substrates of different elasticities. Moreover, the chemical composition of cells was determined using time-of-flight secondary ion mass spectrometry (ToF-SIMS), combined with sophisticated analytical tools, i.e., Multivariate Curve Resolution (MCR) and Principal Component Analysis (PCA). Results: The obtained results demonstrate that discrimination between cell lines derived from healthy and diseased patients is possible based on the analysis of the growth of cells, as well as their physical and chemical properties. In turn, the comparative analysis of the cellular response to altered stiffness of the substrates enables the identification of each cell line, including distinguishing between IPF- and NSIP-derived fibroblasts.

SB203580-A Potent p38 MAPK Inhibitor Reduces the Profibrotic Bronchial Fibroblasts Transition Associated with Asthma

Subepithelial fibrosis is a component of the remodeling observed in the bronchial wall of patients diagnosed with asthma. In this process, human bronchial fibroblasts (HBFs) drive the fibroblast-to-myofibroblast transition (FMT) in response to transforming growth factor-β₁ (TGF-β₁), which activates the canonical Smad-dependent signaling. However, the pleiotropic properties of TGF-β₁ also promote the activation of non-canonical signaling pathways which can affect the FMT. In this study we investigated the effect of p38 mitogen-activated protein kinase (MAPK) inhibition by SB203580 on the FMT potential of HBFs derived from asthmatic patients using immunocytofluorescence, real-time PCR and Western blotting methods. Our results demonstrate for the first time the strong effect of p38 MAPK inhibition on the TGF-β₁-induced FMT potential throughout the strong attenuation of myofibroblast-related markers: α-smooth muscle actin (α-SMA), collagen I, fibronectin and connexin 43 in HBFs. We suggest the pleiotropic mechanism of SB203580 on FMT impairment in HBF populations by the diminishing of TGF-β/Smad signaling activation and disturbances in the actin cytoskeleton architecture along with the maturation of focal adhesion sites. These observations justify future research on the role of p38 kinase in FMT efficiency and bronchial wall remodeling in asthma.

Effects of secretome derived from macrophages exposed to calcium oxalate crystals on renal fibroblast activation

The association between kidney stone disease and renal fibrosis has been widely explored in recent years but its underlying mechanisms remain far from complete understanding. Using label-free quantitative proteomics (nanoLC-ESI-LTQ-Orbitrap MS/MS), this study identified 23 significantly altered secreted proteins from calcium oxalate monohydrate (COM)-exposed macrophages (COM-MP) compared with control macrophages (Ctrl-MP) secretome. Functional annotation and protein-protein interactions network analysis revealed that these altered secreted proteins were involved mainly in inflammatory response and fibroblast activation. BHK-21 renal fibroblasts treated with COM-MP secretome had more spindle-shaped morphology with greater spindle index. Immunofluorescence study and gelatin zymography revealed increased levels of fibroblast activation markers (α-smooth muscle actin and F-actin) and fibrotic factors (fibronectin and matrix metalloproteinase-9 and -2) in the COM-MP secretome-treated fibroblasts. Our findings indicate that proteins secreted from macrophages exposed to COM crystals induce renal fibroblast activation and may play important roles in renal fibrogenesis in kidney stone disease.

Cellular and molecular mechanisms of allergic asthma

Asthma is a chronic disease of the airways, which affects more than 350 million people worldwide. It is the most common chronic disease in children, affecting at least 30 million children and young adults in Europe. Asthma is a complex, partially heritable disease with a marked heterogeneity. Its development is influenced both by genetic and environmental factors. The most common, as well as the most well characterized subtype of asthma is allergic eosinophilic asthma, which is characterized by a type 2 airway inflammation. The prevalence of asthma has substantially increased in industrialized countries during the last 60 years. The mechanisms underpinning this phenomenon are incompletely understood, however increased exposure to various environmental pollutants probably plays a role. Disease inception is thought to be enabled by a disadvantageous shift in the balance between protective and harmful lifestyle and environmental factors, including exposure to protective commensal microbes versus infection with pathogens, collectively leading to airway epithelial cell damage and disrupted barrier integrity. Epithelial cell-derived cytokines are one of the main drivers of the type 2 immune response against innocuous allergens, ultimately leading to infiltration of lung tissue with type 2 T helper (T_H2) cells, type 2 innate lymphoid cells (ILC2s), M2 macrophages and eosinophils. This review outlines the mechanisms responsible for the orchestration of type 2 inflammation and summarizes the novel findings, including but not limited to dysregulated epithelial barrier integrity, alarmin release and innate lymphoid cell stimulation.

Paraquat but not diquat induces TGF-β expression and thus activates calcium-NFAT axis for epithelial-mesenchymal transition

Paraquat (PQ) and diquat (DQ), two highly efficient herbicides sharing similar chemical backbone, both induce reactive oxygen species and are highly toxic to humans and livestock, however, PQ but not DQ poisoning result in pulmonary fibrosis, the leading cause of high mortality rate in patients suffering PQ toxicity. Understanding the unique mechanism of PQ different from DQ therefore would provide potential strategies to reduce PQ-induced pulmonary fibrosis. Here, we identified that PQ but not DQ continuously upregulates TGF-β expression in alveolar type II (AT II) cells. Importantly, such high expression of TGF-β increases cytosolic calcium levels and further promotes the activation of calcineurin-NFAT axis. TGF-β mainly activates NFATc1 and NFATc2, but not NFATc3 or NFATc4. Administration of the inhibitors targeting cytosolic calcium or calcineurin largely reverses PQ-induced epithelial-mesenchymal transition (EMT), whereas DQ has little effects on activation of NFAT and EMT. Ultimately, PQ poisoned patients exhibit significantly reduced blood calcium levels compared to DQ poisoning, possibly via the large usage of calcium by AT II cells. All in all, we found a vicious cycle that the upregulated TGF-β in PQ-induced EMT further aggravates EMT via promotion of the calcium-calcineurin axis, which could be potential drug targets for treating PQ-induced pulmonary fibrosis.

The miR-130a-3p/TGF-βRII Axis Participates in Inhibiting the Differentiation of Fibroblasts Induced by TGF-β1

Pulmonary fibrosis (PF) is a chronic progressive interstitial lung disease that has a poor prognosis. Abnormal activation of transforming growth factor-β1 (TGF-β1) plays a crucial role in fibroblast differentiation. Mesenchymal stem cells (MSCs) are currently being considered for the treatment of PF, but the regulatory mechanisms are poorly understood. We co-cultured bone marrow-derived MSCs and mouse lung fibroblasts (MLg) in the presence of TGF-β1, and studied the protein/mRNA expression of fibrosis markers and related signaling pathways. The effects of miR-130a-3p and TGF-β receptor II (TGF-βRII) on the differentiation of MLg induced by TGF-β1 were studied using immunofluorescence assay, Western blot, and quantitative real-time PCR techniques, respectively. Our results showed that MSCs reversed the overexpression of fibrosis markers and TGF-β1/Smad signaling pathway proteins and mRNAs after TGF-β1 treatment and increased the level of miR-130a-3p. TGF-βRII was identified as a target of miR-130a-3p and was evaluated by dual-luciferase reporter assay. The miR-130a-3p/TGF-βRII axis could suppress the differentiation of lung fibroblasts via the TGF-β1/Smad signaling pathway, thereby reducing the process of PF.

Fibroblast-like synoviocytes: Role in synovial fibrosis associated with osteoarthritis

The synovial membrane undergoes a variety of structural changes throughout the pathogenesis of osteoarthritis (OA), including the development of fibrosis. Fibroblast-like synoviocytes (FLS) are a heterogenous cell population of the synovium that are suggested to drive the fibrotic response, but the exact mechanisms associated with their activation in OA remain unclear. Once activated, FLS are suggested to acquire a myofibroblast-like phenotype that drives fibrogenesis through excessive extracellular matrix (ECM) component deposition and an enhanced contractile function. In this review, we define FLS in the synovium, discuss how select extracellular or endogenous factors potentially induce their activation in OA, and describe how the activity of myofibroblast-like cells affects the structure of the synovial membrane.

miR-20a-5p ameliorates ovalbumin (OVA)-induced mouse model of allergic asthma through targeting ATG7-regulated cell death, fibrosis and inflammation

Autophagy plays an essential role in modulating asthma progression. MiR-20a-5p can regulate autophagy, but its effects on allergic asthma are still unclear. The aim of this study was to explore the potential of miR-20a-5p on autophagy-modulated airway remodeling and to reveal the underlying molecular mechanisms. We found that miR-20a-5p expression was markedly down-regulated in lung of ovalbumin (OVA)-induced mouse model with allergic asthma and in cells stimulated by OVA. Meanwhile, autophagy, apoptosis, fibrosis and inflammatory response were detected in pulmonary tissues from OVA-treated mice. Importantly, luciferase assays showed that ATG7 was a target of miR-20a-5p. We also found that miR-20a-5p over-expression markedly reduced ATG7, while its inhibition promoted ATG7 in cells. In addition, over-expressing miR-20a-5p in OVA-treated cells significantly decreased ATG7 expression levels, along with markedly reduced autophagy, apoptotic cell death, fibrosis and inflammatory response. These results were similar to the effects of autophagy inhibitor 3-Methyladenine (3-MA), indicating that miR-20a-5p was involved in autophagy-induced apoptosis, fibrosis and inflammation. In vivo experiments further demonstrated that miR-20a-5p over-expression was associated with ATG7 reduction in parallel with the alleviated airway remodeling in OVA-treated mice also through suppressing collagen accumulation, apoptosis and inflammation. Similarly, animal studies further confirmed that miR-20a-5p functioned as an autophagy inhibitor to mitigate allergic asthma development. Therefore, miR-20a-5p may be a promising biomarker and therapeutic target during asthma progression by regulating ATG7-modulated autophagy.

Mining Helminths for Novel Therapeutics

Helminths are an emerging source of therapeutics for dysregulated inflammatory diseases. Excretory/secretory (ES) molecules, released during infection, are responsible for many of these immunomodulatory effects and are likely to have evolved as a means for parasite survival in the host. While the mechanisms of action of these molecules have not been fully defined, evidence demonstrates that they target various pathways in the immune response, ranging from initiation to effector cell modulation. These molecules are applied in controlling specific effector mechanisms of type 1 and type 2 immune responses. Recently, studies have further focused on their therapeutic potential in specific disease models. Here we review recent findings on ES molecule modulation of immune functions, specifically highlighting their clinical implications for future use in inflammatory disease therapeutics.

Responsiveness of human bronchial fibroblasts and epithelial cells from asthmatic and non-asthmatic donors to the transforming growth factor-β1 in epithelial-mesenchymal trophic unit model

BACKGROUND

The asthma-related airway wall remodeling is associated i.a. with a damage of bronchial epithelium and subepithelial fibrosis. Functional interactions between human bronchial epithelial cells and human bronchial fibroblasts are known as the epithelial-mesenchymal trophic unit (EMTU) and are necessary for a proper functioning of lung tissue. However, a high concentration of the transforming growth factor-β₁ (TGF-β₁) in the asthmatic bronchi drives the structural disintegrity of epithelium with the epithelial-to-mesenchymal transition (EMT) of the bronchial epithelial cells, and of subepithelial fibrosis with the fibroblast-to-myofibroblast transition (FMT) of the bronchial fibroblasts. Since previous reports indicate different intrinsic properties of the human bronchial epithelial cells and human bronchial fibroblasts which affect their EMT/FMT potential beetween cells derived from asthmatic and non-asthmatic patients, cultured separatelly in vitro, we were interested to see whether corresponding effects could be obtained in a co-culture of the bronchial epithelial cells and bronchial fibroblasts. In this study, we investigate the effects of the TGF-β₁ on the EMT markers of the bronchial epithelial cells cultured in the air-liquid-interface and effectiveness of FMT in the bronchial fibroblast populations in the EMTU models.

RESULTS

Our results show that the asthmatic co-cultures are more sensitive to the TGF-β₁ than the non-asthmatic ones, which is associated with a higher potential of the asthmatic bronchial cells for a profibrotic response, analogously to be observed in '2D' cultures. They also indicate a noticeable impact of human bronchial epithelial cells on the TGF-β₁-induced FMT, stronger in the asthmatic bronchial fibroblast populations in comparison to the non-asthmatic ones. Moreover, our results suggest the protective effects of fibroblasts on the structure of the TGF-β₁-exposed mucociliary differentiated bronchial epithelial cells and their EMT potential.

CONCLUSIONS

Our data are the first to demonstrate a protective effect of the human bronchial fibroblasts on the properties of the human bronchial epithelial cells, which suggests that intrinsic properties of not only epithelium but also subepithelial fibroblasts affect a proper condition and function of the EMTU in both normal and asthmatic individuals.

TGF-β: The missing link in obesity-associated airway diseases?

Obesity is emerging as a global public health epidemic. The co-morbidities associated with obesity significantly contribute to reduced quality of life, mortality, and global healthcare burden. Compared to other asthma comorbidities, obesity prominently engenders susceptibility to inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), contributes to greater disease severity and evokes insensitivity to current therapies. Unlike in other metabolic diseases associated with obesity, the mechanistic link between obesity and airway diseases is only poorly defined. Transforming growth factor-β (TGF-β) is a pleiotropic inflammatory cytokine belonging to a family of growth factors with pivotal roles in asthma. In this review, we summarize the role of TGF-β in major obesity-associated co-morbidities to shed light on mechanisms of the diseases. Literature evidence shows that TGF-β mechanistically links many co-morbidities with obesity through its profibrotic, remodeling, and proinflammatory functions. We posit that TGF-β plays a similar mechanistic role in obesity-associated inflammatory airway diseases such as asthma and COPD. Concerning the role of TGF-β on metabolic effects of obesity, we posit that TGF-β has a similar mechanistic role in obesity-associated inflammatory airway diseases in interplay with different comorbidities such as hypertension, metabolic diseases like type 2 diabetes, and cardiomyopathies. Future studies in TGF-β-dependent mechanisms in obesity-associated inflammatory airway diseases will advance our understanding of obesity-induced asthma and help find novel therapeutic targets for prevention and treatment.